Confuse about how to make a tiles to support retina device
I have a map picture(15772*13796) so I break them to tiles using gdal2tiles(512*512px not 256*265px) for support retina device but is this correct? Because I a had read this issue and this. They are...
View ArticleGenerating a GDAL script through the QGIS Georeferencer
For several months, I have been georeferencing files manually using the Georeferencer plugin within QGIS. I am now attempting to automate this process using GDAL. The Georeferencer provides a “Generate...
View ArticleUse Gdal2tiles to generate 512px tiles
I’m a newbie in gdal2tiles & python but I would like to modify gdal2tiles to create 512px tiles for retina display (screen). Can someone suggest how I can do this?
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How can I use data from PDF map?
I have a map over Sweden with plenty of data represented as circles of various sizes. The map is saved as PDF from Illustrator, fully editable. I wonder if there is any way I could get these circles...
View ArticleHow to correctly resize raster GIS images to a given px width?
I work on ETOPO1, a 466MB file, and want to move to SRTM (~20GB Earth). My workflow involve several time-consuming processing steps so I strongly want to work on a minimum raster. It usually want to...
View Articleogr2ogr update failing to update shapefile int PostGIS
I have a bunch of shapefiles that I am looping in with a bash script to load and update files but the ogr2ogr fails. I am running gdal 1.92 on ubuntu 14.04. for file in `ls *.shp`;do ogr2ogr -progress...
View ArticleImprove gdaldem hillshade output (lighten up flat parts)
I have a hill-shading that I made using gdaldem hillshade which is already pretty good. I used the option -alt 60 to get nice contrast, but the problem is, that with lowering the light-source, also...
View ArticlePython and gdalwarp: change resolution of raster
I am new to GDAL and have been having some hard time figuring out how to change a raster’s resolution and how to align it to another existing raster. I have come to the point where I have a raster made...
View ArticleMapserver: “Premature end of script headers: mapserv,”
Some of requests to the Mapserver return “Internal server error”. When I checked the Apache log I saw that there are several error messages: GDAL: In GDALDestroy - unloading GDAL shared library.,...
View ArticleGeoreferencing a raster using GDAL and Python
I want to georeference a raster using python and GDAL. My current approach is to call gdal_translate and gdalwarp using os.system and an ugly list of ground control points. I’d really like a way to do...
View ArticleHow to get the mapserver WFS OGR driver to encode unicode in geojson
Running mapserver 6.4.1, gdal 1.14.3 I try to output some WFS features using outputformat=geojson. The relevant bits of the mapfile are appended below. Everything works fine, but unicode characters are...
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Re-project from Polar projection to EPSG:4326
I simply want to project a polar stereographic raster (EPSG:3411) to Mercator (EPSG:3857) or WGS84 (EPSG:4326). The data I is from NOAA. $gdalwarp -s_srs EPSG:3411 -t_srs EPSG:3857 northpsg.20141027...
View ArticleConvert PNG to GeoTiff using GDAL
I have a map portion PNG and its associated PRJ file. I want to convert the PNG to a GeoTIFF. I know how to convert a PNG to a GeoTiff if the bounding box is available: gdal_translate -of Gtiff -a_ullr...
View Articlebuilding GDAL with libKML support
I’m attempting to import a kml/kmz file generated using Google Tracks into my QGIS 2.4 system (built with GDAL 1.10). KML files currently lose all attributes, and as such I’m attempting to build GDAL...
View ArticleWhat options are there for geolocation-aware SQL databses?
I need to implement an SQL database that can make queries using geo-location based logic. e.g. select rows within 500m of coordinate x, y What options are available to do this with sqlite, mySQL,...
View ArticleGeoreferencing window won't open QGIS 2.4
I had the georeferencer window open in QGIS 2.4 while project was running, I accidentally closed the Qgs document with the georeferencing window open (worked absolutely fine till then). When I opened...
View Article“fill in” .vrt with missing locations in a mosaic
I have ~2000 NASA SRTM .hgt files. I wanted to join them together in a single mosaic, and to save disk space I used GDAL to create a .VRT rather than a very large GeoTiff. This is read by Mapnik. What...
View ArticleI've downloaded the GDAL-1.11.1 package but why can't I call on it in python?
I have a Mac and am very new to this coding stuff.. I’m using a code that includes import osgeo as gdal and so I’ve downloaded GDAL from https://pypi.python.org/pypi/GDAL/ which has a folder called...
View Articlegdaldem output file size explodes
I want to create a color-relief and a hillshade with gdaldem and use them with mapnik. System: Ubuntu 14.04 LTS Server, gdal-bin 1.10. Here are my steps: Download all SRTM tiles from...
View ArticleAdding a column to several feature classes in a file gdb using ogr2ogr
I’m trying to add the same column to 25 feature classes in an ESRI FileGDB. I managed to do this for one feature class by using ogr2ogr: ogrinfo C:temptest.gdb -sql “ALTER TABLE table01 ADD COLUMN...
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